Disappearing Arctic Ice

It looks as if 2012 will set a new record low for Arctic ice extent[1]. As a measure of the impact of global warming, this is depressingly clear-cut. There’s no need to go into arguments about trends and variability, or use any kind of modelling – the ice is melting visibly.

Arctic Sea ice extent

Source: National Snow and Ice Data Center.

fn1. Satellite data on ice extent goes back to 1979. There are other measures, arguably more relevant, such as estimates of ice volume, for which the data set is shorter. They tell an even gloomier stories.

83 thoughts on “Disappearing Arctic Ice

  1. @Happy Heyoka

    I think Fran is right about storage being important, but “grid-scale” storage is hardly trivial

    I like the idea of using small scale pumped hydro combined with localised water treatment. If we had sewage/waste water pumped to combined district water treatment and catchment systems not only could we save energy transporting water, and make better use of existing water, but we could use surplus power from intermittent sources to pump water to perhaps 50 metres of head pressure and the local catchment vessel. We have near where I live a pumping station perhaps 1.6 km as the corw flies from large water tanks on a hill at probably at least that elevation.

    Taking surplus power to do that job would be very easy but something obviously we could elect not to do when power was in short supply. These mini-pumped storage systems could be the reserve power overnight, allowing both the coal fired and gas peaking stations to be closed/ramped down. Because we could make use of natural terrain, the engineering costs of doing this would be far lower than in most other locations near load centres.

    Another option might involve the V2G system. As more and more plug-in electric vehicles come on line both the vehicles and the battery swap infrastructure could become part of the grid storage system. There’s an obvious advantage from the POV of a battery owner in selling power during peak demand and buying it back during the off-peak, even if one makes allowance for the accelerated decline in the battery life of each cycle. One suspects that if this becomes a major source of redundant capacity manufacturers will begin focusing on how to build batteries capable of avoid deterioration through cycling.

    It also occurs to me that there is an untapped resource in the discarded lead-acid batteries of conventional vehicles. These are a not insignificant disposal problem but I do wonder at the feasibility of reconditioning these batteries for grid storage.

  2. Fran you need to look at the energy storage capacity of water. It is not a lot. Without looking I think that it is around 125 watt hours per cubic meter at 100 meters head. You need to have very large bodies of water to make pumped hydro useful. I don’t think that the tanks on Old Bathurst Road are of a suitable scale. Wentworth Falls lake would be a useful size but then it would be useless for other activities.

    For that scale of infrastructure (water storage tank size) the Redox battery makes more sense as a storage medium. At (originally 20) 40 watt hours per litre, a cubic meter (1000 litres) would store 40 kilowatt hours , or a 30 metre diameter by 10 metre high tank would store 90 megawatt hours times .75 (round trip efficiency). That is a useful amount of storage. That would make 12 kilowatt hours available to 6000 homes.

    That is if my info quick calcs are anywhere near correct.

  3. @BilB

    The figure I’m working with is 0.272kWh per Kl of water (1 M^3). I am assuming a round trip efficiency of about 80% (pipe diameter is a variable here). A 30m tank 15m in height elevated to 50 m head pressure would yield 1442.17kWh when fully discharged. Adjusting for 80% RTE that is 1153.74 kWh. Where the existing topography is suitable, the costs of these would be manageable. We already have places where reservoirs pump to neighbourhoods from elevated positions.

    Batteries have a toxicity and ideally, one doesn’t want to add toxics to the system.

  4. Yes that figure sounds familiar, about twice what I said. I knew it was in that territory, still not particularly wonderful. The Redox system has the advantage of not requiring elevation. in fact it best suits a recessed (submerged) location. The Redox liquid is mainly vanadium particles and sulphuric (?) acid so is not especially toxic, although any release is not acceptable.

    I’m afraid I still prefer the domestic storage solution which covers far more of the user’s needs. Last Friday’s storms, for instance, left us at home without power for several hours, as usual. Regional storage does not solve that sort of occurance, which is so far the most common power problem that our family has after the size of the power bill. So there is my work list. GenIIPV solves the power bill problem, with about 6 kilowatt of storage (at present $4200, but eventually $1200) solves both short term backup storage an external connection problems. Extended low solar periods are largely coped with by the fact that even in these times the system generates up to 30% of its full solar peak. And when all else goes wrong most of the GenIIPV features can be backed up with gas consumption. There is one more link missing, which I am sure we will be able to bridge in due course.

    So on the whole I don’t feel so stressed about the need for regional storage for GenIIPV users. And even for the broader system i think that system size will cope with most of the storage needs coupled with intelligent distribution which can trigger things like off peak water heating to absorb supply overloads.

    Summary. I am less concerned now about storage now than I was several years ago during all of those wasted arguments with anti solar energy alarmists like Peter L. Also if you Google around you will see that there are serious companies such as Siemens and The Switch providing significant industry standard mass energy storage solutions for wind power load leveling.

  5. I forgot to multiply by Pi in my calculation, Duh.

    So your Old Bathurst Road tank would as a Redox tank store 424 megawatt hours unless I’ve made yet another mistake. Alternatively to achieve the Redox tank size to store the 1442 kilowatt hours is just 36 cubic metres, or a tank 6 x 6 x 1 metre high. There is a massive difference in the energy density there.

  6. So just working through the implications of the above if we had across the Sydney conurbation — (i.e the area bounded by Newcastle/Hunter to the north, Wollongong in the South and Lithgow in the West) you could have in pumped storage alone about 173MWh taken from surplus generation of about 216MWh.

    It’s hard to find out how much wind/PV we have in NSW but across the country in 2010 about 5400 MwH in solar PV and Wind were consumed. Assuming 30% of that was in NSW the surplus generation should be a lot lkess than 216 MWh.

  7. @BilB

    I think there should be a mix of options but the pumped storage option colocated with local reservoirs sounds appealing as part of the mix precisely because at the margins it wouldn’t require a lot of new infrastructure. We have to store (and treat) and pump water anyway and we can decide when it is convenient in demand terms to do that. Processing water locally has energy advantages.

    If we had much more high density housing we could have even more locally based energy storage since the scope for complexes to run large scale solar on the rooves and store the power in batteries and so forth would be greater than would be the case for individuals. Parking spaces could facilitate V2G connectivity and draw down power directly from their own panels.

  8. Fran, you have to take into consideration that to recover the potential energy from you elevated water tank, you need to have a reservoir tank for the water to flow freely into at the bottom. You cannot let the water drain slowly back through the elevation pump and somehow recover the energy, that is not how they work. Furthermore the water at the bottom has no pressure. In our area there is enough water in the Nepean river for low volume pumped storage but the head tank would only be useful for that purpose. It obviously could not be used for drinking water. The Castlereagh Rise might have enough elevation to do something useful in that way.

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